Botten patent U.S. Pat. No. 7,326,190 discloses a high performance deodorizing gas filter assembly for body waste collection pouches in which a radial flow filter pad is located in an envelope having first and second openings laterally spaced from each other. In a preferred embodiment, the pad is oblong or elongate and has a first passage communicating with the envelope's first opening and a second passage spaced laterally from the first passage and communicating with the envelope's second opening. Flatus gases may therefore enter the first passage through the first opening, flow in generally radial directions through and about the filter to the second passage, and exit from the envelope through the second opening. Hydrophobic microporous membranes extend over each of the openings to prevent liquids from entering the envelope and impairing operation of the filter while at the same time allowing gases to flow therethrough. While such an arrangement achieves impressive filtering performance in terms of gas transmission rate and deodorizing efficiency, such achievements are obtained by reason of a radial flow filter assembly of relative large area or outline.
Villefrance patent U.S. Pat. No. 6,506,184 is also directed to the use of radial flow filters for body waste collection pouches and shows that they may be located inside, outside, or both inside and outside such pouches (see FIGS. 2, 4 and 6, respectively). Other patents disclosing radial flow filters are Keyes U.S. Pat. No. 5,370,638, Poulsen et al U.S. Pat. No. 4,460,392 and Nolan et al U.S. Pat. No. 3,759,260.